Controlling and operating means for engines, for underfeed stokers, and the like



D. F. GRAHAME AND OPERATING MEANS FOR ENGINES, FOR UNDERFEED Nov. 24,1925.

CONTROLLING STOKERS, AND THE LIKE Filed July 1, 1922 5 Sheets-Sheet 1NNN NNRN Now 24 \1925.

5 Sheets-Sheet 5 Y J2 M6711???" ZQZZQSZ6 TQ7Z ZM3 D. F. GRAHAMECONTROLLING AND OPERATING MEANS FOR ENGINES, FOR UNDERFEED STOKERS, ANDTHE LIKE Filed July 1. 1922 fl0a, 4 M%%Q Nov; 24, 1925. 1,562,634

F. GRAHAME D. CONTROLLINGVAND OPERATING arms FOR ENGINES, FOR UNDERFEEDSTOKERS,'AND THE LIKE Filed July 1. 1922 5 Sheets-Sheet 4.

Nov. 24, 92 1,562,634

D. F. GRAHAME 'comnouuue AND OPERATING mums FOR ENGINES, FOR UNDERFEEDSTOKERS, AND THE LIKE Fil d J l 1922 5 Sheets-Sheet 5 A 72 z /e72f071'Patented Nov. 24, 19925.

UNITED STATES 1,562,634 PATENT OFFICE.

' DALLAS F. GRAHAME, OF TORONTO, ONTARIO, CANADA. ASSIGNOR, BY MESNEASSIGN- MENTS, TO RILEY STOKER CORPORATION, OF WORCESTER, MASSACHUSETTS,A

PORATION OF MASSACHUSETTS.

CONTROLLING AND OPERATING Application filed July 1,

To all whom it may concern:

Be it known that I, DALLAS F. GRAHAME, a subject of the KingofGreatBritain, and a resident of Toronto, in the Province of Ontario, in theDominion of Canada, have invented certain new and useful Improvements inControlling and Operating Means for Engines, for Underfeed Stoker-s, andthe like ef which the following is a specification.

My invention provides advantageous means for operating, and forcontrolling the operation of, a plurality of engines that are actuatedby fluid pressure from a common source; and in some of its aspects it ismore particularly intended to improve the flexibility of operation andof control of stoker ram-driving mechanisnfio-f the general characterset forth in my co-pending application Serial No. 545,044, filed March28, 1922.

One of the objects of my present invention is to provide for a pluralityofengines arranged to be operated from a common source of fluid pressuresupply, such as a liquid pump, means for controlling the operation ofeach engine so that each individual engine may be cut out of operationwithout preventing the functioning of any other. enthe cut-out valve;Fig. 6 is a top-planyiew gine of the series, and/or each individualengine may be made to work in its own selectively-determinedperiodicity, but with the engines always working one at a time.

Another object of my invention is to provide advantageous valving meansoperatable under pro er control'to out out of service or as I wil termit for brevity) disable that engine with which it is connected.

i battery of engines for A further object of my invention is to pro videsimple, effective and easily adjustable means, individual to eachengine, by which the 0 erator'may selectively set the enginedisab ingmeans (such as the valvingmeans referred to) for desired periodicity ofoperation.

Another object of my invention is to provide hydraulic actuatingmechanism for a r'iving Stoker-rams or the like. which will be simple,inexpensive, easily installed and maintained, eflicient and .givingdesired flexibility in the operation of the respective engines.

Other and further objects of my invention on the broken section line 33of Fig. 4; Fig. 4 is a transverse section of said mechaparts as seenfrom below Fig. 9.

COR-

MEANS FOR ENGINES, FOR UNDERFEED STOKERS, I

AND THE LIKE.

1922. Serial No. 572,240.

will become apparent to those skilled in the art from the followingdescription taken in conjunction with the accompanying drawings in whichI have shown the application of my invention as applied toStoker-driving mechanism and wherein, for purposes of dis} closure, 1have mainly illustrated the same in diagrammatic fashion; and it will beunderstood that the specific structural embodiment shown and thearrangement which I illustrate may be widely varied, and that thecontrolled engine may be utilized for various kinds of work, within thespirit of my invention and in the scope of the appended claims.

In the drawings, Fig. 1 is a diagrammatic representation of theapplication of my invention to a stoker-drive; Fig. 2 is a detaildiagram of a valve operating means shown in Fig. 1;. Fig. 3 is a sectionof an engine cut-out valve, with parts in elevation, taken nism taken online 44 of Fig. 3; Fig. 4* is a detail of the controlling valve; Fig. 5is a front elevation with parts broken away of a step-by-step operatingmechanism for of Fig. 5; Figs. 7, 8 and 9 are views similar differentwo'gking positions; and Fi "10 is an inverted plan viewef Fig.9 showingthe 86 A, battery of engines is diagrammatically illustrated as comrising only three, although any suitabl number may be provided. Engines20, 20 and 20", I call, for convenient identification, the first,intermediate and last engine, and while I shall describe parts withparticular reference to the first engine 20, in most instances, similarparts of other engines are indicated by like numerals ofreferencedistinguished by the exponents a and b.

Engine 20 comprises cylinder 21 and pi'ston 22, the latter havingits'piston rod connected to astoker ram or plunger R' for the boiler 13,all pistons being shown in home position, so to term theposition attheir instroke end where they rest between feedingoperations. For 0erating the en 'nes, a fluid, preferably oi will be suppli underrequisite pressure from a pump 23 driven by an electric motor or othersuitable prime mover 23, the pump being connected to draw on reservoir24 and,-through the pipe 25 and pressure-alternating valve 26', tosupply the liquid under pressure alternately to the two feed pipes 27and 28 that respectively lead to the first engine and the last engine.At substantially all times valve 26 connects one feed pipe to thepressure pipe 25 from the pump, while connecting the other feed pipe tothe return duct 24' of the reservoir 24. Reversing valve 26 is suitablyoperated to stand in the position shown in Fig. 1 long enoi'igh toenable the pressure supply through feedpipe 27 to drive all enginepistons of the battery 011 their outstrokes, and upon reversal of thevalve or movement to opposite extreme of position in its cylinder it.'will then supply pressure to the feed pipe 28 for an equal length oftime. Valve 26 is thus merely one simple means of alternating thepressure application or direction of fluid flow between the feed pipesthat lead to the opposite extreme engines, and its frequency ofoperation may be varied as by means hereafter described directly toaffect the frequency of operation of all of the engines.

he engines have interconnections be tween their cylinders arranging themin series or succession, these connections being so disposed that thepiston of each engine may act as a controlling valve for the engine orengines posterior to it in the then existing direction of pressure flowthrough the piping. Thus, in the diagrammatic illustration of Fig. 1,pipe 27 which is receiving pressure from pump 23 has open connectionwith a passage 29 leading directly into the inner end of the cylinder ofengine 20, While, through passages to be described, the outer end ofthat cylinder has open communication with the return pipe 28. As piston22,

driven by the pressure approaches its outgine 20 just beyond the homeposition of the stroke position it passes the port for pipe .30 which isconnected to the passage 29? for the next or intermediate engine,conditioning that engine to effect its piston out-stroke, in

turn to open pipe 30 for the next engine of the series. Of course whenthe last engine has effected its piston out-stroke, all engines remainidle in the stated condition pending reversal of the valve 26. Thefurther connections between the engines whichserve as return flowpassages on the above stated outstrokes of the plstons will, after theirreversing valve has moved, direct the reverse p pressure through theengines seria'tim from left to right or 'in reverse order, While theheretofore described. passages 29,. 30, etc, will, under these reverseconditions, act as thereturn'passages. Engine cylinder 21' normallyhas-its outer end connected bya passage 31 andpipe 32. with a port ofen- In the general organization thus far described, my present systemaccords with that set forth in my pending patent application aforesaid.

Further, where the invention is used in hydraulically driving stokerrams, the control over the reversing valve 26 may be exercised by meanssubstantially asset forth in said application, and in the presentdrawings the steam pressure in boiler B may govern a regulator R for arheostat 1' that governs the speed of an electric motor M for the stokerblast fan F, from the shaft of which is driven the mechanism thatreverses valve 26. Through vbelting and pulleys P the gears G aredriven, one of them carrying. a suitable cam mechanism 0 to act on thestem 26 of the hollow valve 26 to reciprocate it. As boiler pressurerises fan speed is out down, and withit the frequency of reciprocationof valve 26 and the feeding capacity of the ram battery as a whole, Asboiler pressure drops both air and fuel supplies will be augmented.

To attain one of the objects of my present invention I provide inconnection with each engine a valve arrangement 35 by which that enginemay be put out of service or disabled, so that its piston will remain inhome position when, pressure is being supplied to the engine batterythrough the supply pipe 27, this disabling of the selected engine beingso .accognplished that it does not interfere with the operation of anyother engine in the bat tery. And for selective operation of each whichcommunicates with passage 29, and a passage 39 which leads through thecylinder wall ust beyond the home position of the piston. When pressure,from feed pipe 27' raises this valve, the piston in its home position isbypassed; pressures on opposite sides of the piston are substantiallybalanced, and the piston will not make an outstroke. With the. specificarrangement of piping connections between the cylinders that has beenabove described,and which I prefer to employ, it is necessary that the.normally open connection between passage 31 and pipe 32 be closed,while liquid is flowing through the by-pass valve aforesaid, in order toinsure that the pressure thus bypassed around the one piston shall beexerted through the pipe 30 to actuate the next engine in the series (ifsuch next engine be otherwise set for normal operation). In order toaccomplish the cutting off of communication between pipes 31 and 32*, asecond valve-element or head 40 is connected to and movable with thestem of by-pass valve 37 This valve-element 40 may be one head of aspool-shaped valve-and-piston structure, as shown in Figs. 3 and 4 andwhen such structure moves to the position shown in Fig. 3 the part 40closes the ports for the two passages 32 and 39. In the normal positionof the valving parts (shown in Fig. 4)

the passages 32 and 39 communicate with each other through thevalve-channel 41 in tervening between valve-head 40 and the piston-head,42, of said valve-and-piston structure. This piston head 42 works in acylinder 43 in which a light spring 44 may be provided to aid innormally maintaining the valve 37 closed.

The cut-off valve structure may be operated in various ways. but Iprefer to provide that structure, as shown, in the form of apressure-actuated valve governed by a rotatable pressure-relief valve,which in turn is actuated by the selective mechanism 36 which thuseffectively controls the periodicity of operation of the cut-off valvestructure.

The piston head 42 exposed to cylinder 43.

is preferably largerthan the area of valve 37 exposed to passage 38, sothat as long as pressure from passage 38 is freely applied to both theunder side of the valve and the top of the piston, the valve will remainclosed. Controlling valve 46 establishes such ,a pressure connectionduring the major portion of its rotative cycle. It

has a peripheral groove 49 throughout the major portion of itscircumference which will connect the port 50 from cylinder 43 with apassage 51 leading through the valve shell to passage 38. At oneposition in its rotation, however, valve 46 cuts 011' the normally openconnection through passage 51 tothe passage 38 and connects port 50 witha relief passage 52 that opens past backcheck valve 52 into the passage39 above Longitudinal duct 54 in the ro- .tatable valve effects suchrelief connection,

valve 37.

as shown in Figs. 3 and 4. The valve 46 is rotated step-by-step by theselective mechanism, with the cut-off valve structure re?" mainingineffective as long as channel 49 is open to port 50, but when the valveis stepped to the position shown in Figs. v3 and 4 the next succeedingpressure impulse communicated from the pump through pipe 27 will raisethe cut-off valve structure from the position shown in Fig. 4 to thatshown thus (except for the omission or plugging of useless ports) thephysical structure above described may remain unchanged for uniformityof equipment.

The selective controlling mechanism for rotating the valve "46 may beconsiderably varied, but in the preferred mechanism shown I make allselectors alike and op,- erate them all by respective links '58 from.28, no valve element 40 need be provided,

crank arms59 on a rock shaft 60 which is reciprocated, in unison, withreciprocations of reversing valve 26. by a piston 61 arrangedin acylinder 62 that has its opposite end piped as at 27' and 28 to therespective feed pipes 27' and 28, the piston rod having a crankconnection 63 to rock shaft-60. Each link 58 operates its correspondingpawl carrier 65 loosely mounted .on the valve stem 66 (Fig. 4), the mainpawl 67 on one end of said carrier coacting with the main ratchet wheel68 that is fastened to the valve shaft 66. The pawl reaches laterallyfrom position for engagement with the ratchetteeth 69 across the planeof a shield segment 70, which is loosely adjustable coaxially with shaft66 to vary. the number of teeth that may be engaged the pawl for'elfectuating a movement 0 the ratchet wheel, and thereby to vary thelength of throw of the ratchet wheel and the valve effected by eachreciprocation of the pawl carrier. This shield has a projecting arm 71that may be latched by a pin 72 in any .one of the indexing apertures 73on frame plate 74, Fig. 5 showing the shield set to permit full strokeoperation of the pawl; Fig. 7 showing the setting for I shortest orsingletooth throw of the pawl;

Fig, 8 showing-an intermediate position and Fig. '9 showing theshieldplate permanently lifting the pawl as may be desirable to hold oneengine] permanently disabled.

It is desirable thatprovision be made so that; whatever may be theeffective to0thprogression accomplished by each stroke of the pawlcarrier "under the variable settings provided for, the rotatable valve46 shall always, at one stage of the rotation thereof, be broughtaccurately to position registering its passage 54 with the port 50 forrelief of pressure in valve cylinder 43,

and .on the next stroke of the pawl carrier shall fully remove. thepassage 54 from such communication. To this end a secondary pawl 76 ismounted on the opposite end of carrier 65 to cooperate with a secondaryratchet wheel 77 that has only two notches 78 and 7 8, so spaced thatwhen the leading one of said notches is engaged the secondary pawl 76 atfull retraction, and moved forward a full stroke, it accuratelypositions the valve in relief station, and posi vtions the following;notch 78 to receive the secondary pawl 76 at the end of the nextretraction, so thaton the next operating stroke of the pawl carrying armthe valve may be carried fully out of relief position. It is manifestlydesirable, in this connection, to leave smooth or toothless such are ofthe primary ratchet wheel as will make 'the .movement of the valvefinally into and fully away from relief position wholly dependent on thesecondary pawl. Also. it is desirable to connect with the projecting orsetting arm 71 some appropriate means, such as pin 80, to throw thesecondary pawl positively out of range for engaging notch 78 when theindexing arm is set in zero position as shown in Fig. 9 to permit apermanent disabling of its afl'ected engine. This pin 80 may thereforeact on a lip 81 on the pawl. Since also it may be desirable'on occasionto rotate the valve manually, instead of automatically, a turning handle83 may be provided on the extreme end of the valve shaft 66. I v

In rsum of the operation: The boiler pressure 'afl'ects the regulator Rto modify the speed of the prime mover Mfor fan F to vary the supply ofair to the underfeed.

.a frequency dependent upon the boiler pressure, although theperiodicity of.operation of each engine relativelyto the periodicity ofoperation of other engines in the battery may be varied or any one ormore engines may be cut out of service without disabling the others.From the fan shaft is driven the gearing G that reciprocates thereversing valve 26 by which, alternately, the working pressure of pump23 is turned into the feed pipe 27 or into the feed pipe 28, theremaining one of said pipes being connected at the return pipe to thereservoir 24. As the reversing valve 26 is. reciprocated, so 1s thepiston 61 reciprocated to rock the shaft which actuates the'step-by-stepselective mechanisms for the respective cut-ofl' .valve structures 35 ofthe several engines of the battery. With none of said valve structures35 in disabling position, pressure from plpe 27, communicated throughpassage 29 w1ll drive from home position the p1ston of the first engineuntil it opens the connection 30 whichcommunicates with the inner end ofthe cylinder for the second engine, and so on throughout the series, thefluid ahead of each engine piston being driven through the returnpassage from cylinder to cylinder via the connections 31, 32, etc., allof which will be open under. the conditions stated. Accordantly the enines make, in sequential order, their respective outstrokes, the minimumfrequency of movement of valve 26 being enough to enable this to beaccomplished before a valve reversal takes place. When the valvereverses the direction of pressure flow through the series connectedcylinders is reversed and all engines (but in reverse order) make theirinstrok'e or piston returns to home position. With each reciprocation ofthe piston 61 (concurrent with reversals of the valve 26) the rotarycontrol valve 46 for each engine has imparted to it a rotative step ofsuch len th as is determined by the setting of the se ective mechanism36 appurtenant to that valve. During most of the rotation of each valveits long channel 49 keeps the pressure passage 38 in communication,through passage 51 and port 50, with the cylinder 43 of thepressure-controlled cut-off valve. Piston 42 being of larger effectivediameter than valve 37, said valve 37 will remain constantly closedunder this condition. Finally, chamber 43 is relieved when valve 46reaches the position shown in Fig. 3, by the opening of the valvedconnections 50, 54, 52 to the upper side of the by-pass valve 37.Consequently on the next occurrence of a pressure impulse through pipe27 valve '37 will be forced 0 en, and will carry up with it thenon-inter erence valve 40 to close off the normally opened connectionbetween passage 31 and pipe 32. Assuming it is engine 20 whose valve hasthus opened to bypassing position, it will be seen that pressure fromfeed pipe 27 may flow through the 0 en valve 37 and passage 39 into thecylin erv beyond the home position of the piston 32, leaving that engineinert, or in other words, disabling its piston temporarily. The pressureapplication proceeds through pi e 30 to thenext engine of the series,whic may thereupon operate to take its out-stroke, and so on throughoutthe rest of the battery. The pressure thus released into cylinder 21through the connection 39 cannot find escape through the return pipe 28via the passage 31 for the reason that said passage is' cut-ofl' by thenon-interference valve 40. Inorder permanently to cut any engine out ofservice it is only necessary to turn the indexing handle 71 to zeroposltion as shown in Fig. 9, wholly disabling the ratchet and pawlmechanism, and manually to bring the rotary controlling valve 46 to theposition shown in Flg. 4 by turnin the handle '83 to the uprightposition in icated in Figs. 7 and 9.

While I have herein described in considerable detail a specificembodiment of my invention it will be understood thatin its broaderaspects I do not desire to be limited to the details shown (except assome refinements are claimed for their specific advan tage), and thatmany changes iii construction, arrangement and operation of variousparts may be made without departure from the spirit of my inventionwithin the scope of the appended claims.

I claim: 1. In combination, a plurality of engines to be operated, meansfor supplying pressure alternating in direction to said engines,

connections between said engines to transfer pressure from one toanother thereof normally to provide for their operation in successlon,and means associated with one of said engines to render said engineinoperable by said alternating pressure Without disabling any other ofsaid engines.

2. The combination of a plurality of engines, means for supplyingactuating pressure alternately to the opposite extreme ones of saidengines, pressure-transfer connec tions between sald engines forpressure transfer from one to the other normallyto operate saidenginesinpredetermined succession, and means associated with each said enginerespectively, operable to by-pass the pressure with respect to saidengine without disabling any other engine.

3. The combination of a plurality of reeiprocatory engines,interconnections between the several engines of the series for pressuretransfer from one to another, a liquid pump, connections including areversing 'valve for connecting said pump alternately with the extremeengines of the series, and means for cutting out of operation any engineof the series.

4. In combination, a plurality of engines to be operated by analternatingly directed fluid pressure, connections between said enginesto transfer pressure from one to another thereof td operate themnormally in succession, means associated'with' each said engineoperatable to render said engines non-responsive to the stated pressure,and se- 'lective timing mechanism for automatically operating the lastsaid means.

5. In combination, a plurality of engines, means for supply liquidpressure alternately in opposite directions to the extreme ones of saidengines pressure transfer connections between sai engines in series tonormally condition each engine for pressure response as the result ofpiston movement of its predecessor in the series, and-means associatedwith each engine for iby-passing pressure arbund its piston. I

6. In combination, a plurality of engines gines, series connected forsingle successive then in opposite order on their in-stroke,

and means for by-passing pressure around one of said engines when itspiston is'in instroke position.

8. The combination with a plurality of engines normally connected inseries for successive operation of their pistons by pressure supplied tothe extreme engine, and means for bypassing the pressure aroundanyengine of the series.

9. The combination with a plurality of enoperation in response topressure alternately supplied to opposite ends of the extreme ones ofsaid engines, and means connected with each engine of the series forby-passing pressure around its piston without disabling any other engineof the series, and means for operating any said by-passing means atwill.

. 10. The combination with a plurality of engines, series connected forsingle successive operation in response to pressure alternately suppliedto opposite endsof the extreme ones of said engines, and means connectedwith each engine of the. series for by-passing pressure around itspiston without disabling any other engine of the series, and means forautomatically actuating each by-passing means after a selectivelydetermined number of im ulses of pressure.

11. The combinatlon'with a plurality of engines, series connected forsingle succesnately supplied to opposite ends of the extreme. ones ofsaid engines, and means connected with each engine of the series forby-passing pressure around its piston without disabling any other engineof the series, and means for automatically actuating each by-passingmeans after a number of pressure lmpulses selectively determined forthat 120 individual engine.

12. In combination, a plurality of engines to be operatedby pressuresupplied alternately inopposite dlrections to opposite ex-. treme onesof said engines, pressure transfer connections between said engines inseries for their normal operation in predetermined succession, cut-oftvalve means associated with one of said engines for by-passing the jpressure around the piston'for saideng ne, and variablys'ettable meansfor condltionmg sive operation in respdnse to pressure alter- Iconnections between the engines for presend of the first engine to iustbeyond the insure transfer from one to another in series, including,between the first and second engine, and so on throughout the series,normally open connections from the out-stroke stroke position of thepiston for the next engine and from the inner end of the second engineto a point just inwardly from the out-stroke position of the cylinder ofthe first engine, a by-pass connection for the first engine, and avalve, normally closing said by-pass', arranged when open to close theconnection from the outer end of said first engine cylinder to, thesecond engine cylinder. 14. The'combination of a plurality of'engineseach having a cylinder and piston, means for alternately supplying fluidunder pressure to the inner end of the first engine and the outer end ofthe last engine, normally open series connections between said enginesincluding a power-flow connection and a return flow connection, andmeans associated with the first said cylinder for bypassing pressurearound its piston to the power flow connection of the next cylinder,said means including a valve movable to close the return flow connectionfrom the first engine to the-second as the by-passing connection for thefirst engine is opened.

15. The combination with a plurality of engines, hydraulic actuatingmeans connected therewith normally in series thereby to operate saidengines in predetermined sequence, and hydraulically actuated valvemeans for cutting out of operation any selected engine of the series.

16. The combination with a plurality of engines, hydraulic pressureactuating means therefonarranged normally to operate said englnes 1npredetermined sequence, and hydraulically actuated valve means forcutting out of operation any selected engine'of the series withoutdisablin the remaining eng1nes, said valve means includingavalvegovernlng mechanism and automatic means for periodicall operatingsaid mechanism.

17. The com ination with a plurality of engines, hydraulic pressureactuating means therefor arranged normally to operate said engines inpredetermined sequence, and hydraulically actuated valve means forcutting out of operation any selected engine of the series w1thoutdisabling the remaining engines, said valve means including avalvegoverning mechanism and automatic means or periodically operatingsaid mechanism, includ ng ratchet and pawl mechanisms.

18; The combination with a plurality of engines whereof the extreme oneshave feed pipe connections to their opposite ends, hydraulic pressuresupply means for supplying pressure alternately to said feed pipes,pressure transferring interconnections be tween said engines normally tooperate them in sequence on their out-strokes and in reverse sequence ontheir in-strokes, valve means connected with each engine for renderingit individually non-responsive to pressure application tending to moveit on its out-stroke, said means including a valve for by-passingpressure around the piston of said engine.

19. The combination with a plurality of engines whereof the extreme oneshave feedpipe connections to their opposite ends, hy-

draulic pressure-supply means forisupplying pressure alternately to saidfeed-pipes, pressure-transferring interconnections be tween said enginesnormally to operate them in sequence on their outstrokes and in reversesequence on their in-strokes; valve-means connected with each engine forrendering it individually non-responsive to pressure a plication tendingto move it on its out-stro e and including a valve for by-passingpressure around the piston of said engine, said by-pass valve beingitself ada ted to be pressure-operated; and a rotatab e valve forcontrolling the application or release of pressure to saidtby-passingvalve for operation of the latter.

20. The combination with a pluralityof.

engines whereof the extreme ones have feedpipe connections to theiropposi ends, hydraulic pressure-supply means for supplying pressurealternately to said feed-pipes, pressure-transferring interconnectionsbetween said engines normally to operate them in sequence on theirout-strokes, and in reverse sequence on their .in-strokes; valve-H meansconnected with each engine for rendering it individually" non-responsiveto pressure application tending to move' it on its out-stroke andincluding a valve for bypassing pressure around the piston of saidengine, said by-pass valve being itself adapted to be pressure-operated;a rotatable valve for controlling the application or'release of pressureto said by-passing valve for oporation of the latter, and means forautodering it individually non-responsive to pressure applicationtending to move it on its out-stroke and including a valve for bypassingpressure aroundthe piston of said engine, said by-pass valve being itself adapted to be pressure-operated; a rotatable valve for controllingthe application or release of pressure to said by-passing valve foroperation of the latter, and means for automatically operating saidrotary valve including a ratchet and pawl mechanism comprising meanssettable to vary the steplength thereof and means operatable regardlessof such step-length to bring said rotary valve invariably to properrelief position and in a single stroke to move it fully out of reliefposition.

22. In an underfeed stoker drive, the combination with the boiler, fuelfeeding rams and reciprocatory engines for said sure and operativelyconnected to a part of said hydraulic system automatically to vary theperiodicity of operation of said reversing valve, and means foroperating said step-by-step mechanism, accordantly with the operationsof said reversing valve.

DALLAS F. GRAHAME.

